JP4004215B2 - Laser processing method and laser processed product - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing method, and more particularly to a method for performing processing such as overlaying, welding, or quenching on a workpiece by irradiating a laser beam.
[0002]
[Prior art]
Conventionally, for example, when an engine supply / exhaust valve seat is overlaid with a laser beam, as shown in FIG. 14, an annular groove formed in advance in a valve seat portion 1 of a cylinder head as a workpiece. The laser beam L condensed by a parabolic mirror 3 is rotated with respect to the continuously supplied powder 2 while rotating the cylinder head while continuously supplying the powder 2 of the cladding material from a nozzle (not shown) to 1a. Are oscillated by the oscillating mirror 4 while oscillating in the radial direction with a predetermined amplitude and frequency, so that the beads (cladding beads) B are continuously formed along the annular groove (processed portion) 1a. At this time, the shielding gas is supplied to the irradiation region of the laser beam L from a gas nozzle (not shown).
[0003]
Further, for example, in the case of butt welding with a laser beam, as shown in FIG. 15, two plate materials 5 and 6 as work pieces are butted together, and the torch 8 is moved along the butt portion 7. The laser beam L emitted from 8 is irradiated to the abutting portion 7 while oscillating at a predetermined amplitude and frequency in a direction orthogonal to the abutting portion 7 by the movement of the torch 7, and a bead (weld bead) B is applied to the abutting portion ( (Processed part) 7 is formed continuously. In the figure, reference numeral 9 denotes a transmission fiber for transmitting a laser beam to the torch 8.
[0004]
[Problems to be solved by the invention]
  That is, the conventional laser processing is performed in the processing longitudinal direction along the processing parts 1a and 7 of the workpiece regardless of the above-described overlay processing (FIG. 14) or welding processing (FIG. 15).Beam LTherefore, if the length of the processing parts 1a, 7 is long, that is, the processing length is long, it takes a long time to scan, and it is inevitable that the productivity is reduced. There was a problem.
[0005]
In addition, when the processing site 1a has a closed loop shape as in the above-described processing of the valve seat, since the processing start end and the processing end overlap, the processing proceeds under the same conditions. For example, defects such as cracks, undercuts, or component dilution due to overheating occur in overlaying, defects such as craters occur in welding, and tempering occurs in quenching. Therefore, conventionally, measures such as gradually reducing the output within the overlapping range of processing have been taken, but control is complicated, and in addition, tempering is completely eliminated by this measure in quenching. There was a problem that I could not do it.
[0006]
For example, Japanese Patent Laid-Open No. 2000-94167 discloses a processing point where a center line of a nozzle for supplying a build-up material and an irradiation center line of a laser beam intersect from the start of processing to the end of processing. In this case, it is described that the generation of cracks and thinning in the overlapped portion (overlap portion) of the processed layer is prevented, but even in this case, complicated control is still necessary. .
Further, for example, in Japanese Patent Application Laid-Open No. 57-140817, when a plate surface of a disk-shaped workpiece is surface-quenched, a laser beam is scanned on the plate surface in a spiral shape (spiral shape). In this case, it is described that the overlap between the machining start end and the machining end itself is eliminated, but in this case, the machining (working layer) overlap in the radial direction is unavoidable, and the fundamental solution is not achieved.
[0007]
The present invention has been made in view of the above-described problems, and the object of the present invention is to drastically change the processing time by radically changing the irradiation shape of the laser beam on the workpiece and the scanning direction. Another object of the present invention is to provide a laser processing method capable of shortening and eliminating a process overlap and improving the processing quality stably.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1By irradiating the workpiece with a laser beam so as to be focused at the processing site,The laser beam irradiation shape is linear in the processing longitudinal direction of the workpiece, and the laser beam shaped into the closed loop shape is shaped into a closed loop shape according to the processing site of the closed loop shape,While maintaining its linear shapeThe processing portion is processed by scanning in the processing short direction of either the diameter reducing direction or the diameter expanding direction.
  In the laser processing method performed in this way, the laser beam shaped in the processing longitudinal direction is scanned in the processing short direction and the processing proceeds in the processing short direction, so that the time required for the scanning is greatly reduced. .
[0009]
  In addition, since the laser beam shaped into a closed loop shape is scanned in either the reduced diameter direction or the expanded diameter direction, the processing start edgeThere is no overlap between the machining end.
[0010]
  Claim 2The invention according to the aboveClaim 1According to the invention, the optical system is operated to rotate the laser beam at a high speed so as to artificially shape the irradiation shape of the laser beam into a closed loop shape.
  In the laser processing method performed in this way, the irradiation shape of the laser beam can be set to an arbitrary size only by operating the optical system.
[0011]
  Claim 3The invention according to the aboveClaim 1The invention is characterized in that the irradiation shape of the laser beam is shaped using a laser diode array arranged in a predetermined shape.
  In the laser processing method performed in this way, a laser is selected according to the irradiation sitebeamTherefore, it is possible to process a processed part having irregularities.
[0012]
  Claim 4The invention according to the aboveClaims 1 to 3In the invention described in any one of the above, the processing on the processing site is one selected from overlaying, welding, and quenching.
  Claim 5The invention according to the aboveClaims 1 to 4A laser processed product processed by the laser processing method according to any one of the above, characterized in that there is no overlap of processed layers.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0014]
1 to 4 show a first embodiment of the present invention. In the first embodiment, the valve seat is intended to be overlaid by a laser beam, and the valve seat portion 1 of the cylinder head as a workpiece is provided with a processing portion as shown in FIG. An annular groove 1a is formed. In the first embodiment, a laser oscillator 12 is formed by assembling a plurality of (here, four) planar fan-shaped stack blocks 11 each including a plurality of laser diode arrays 10 so as to form a cylindrical shape. The laser oscillator 12 is prepared and disposed so as to face the valve seat portion 1. Each stack block 11 can move forward and backward in the radial direction of the laser oscillator 12, and the laser oscillator 12 expands and contracts its diameter as a whole in accordance with the forward and backward movement of the stack block 11 in the radial direction. It becomes like this.
[0015]
As shown in FIGS. 3 and 4, the laser diode array 10 has a rectangular plate shape and includes a plurality of laser emission ports 13 on one surface thereof. The laser diode array 10 also includes a microlens 14 on one surface provided with the laser emission port 13, and the laser beam emitted from the laser emission port 13 passes forward as a parallel beam 15 through the microlens 14. The light is emitted. As an example, each laser emission port 13 has a length s of about 100 μm and a width t of about 1 μm. The width T of the parallel beam 15 is about 1 mm as an example.
[0016]
  In the first embodiment, each laser diodearray10 are built in each stack block 11 so as to be radially arranged at the axial center of the laser oscillator 12 (FIG. 2), whereby a laser beam of a predetermined width has a slight gap from the laser oscillator 12. Arranged in a cylindrical shapeApproximationA cylindrical beam 16 (FIG. 1) is emitted. Thus, the respective stacks 11 constituting the laser oscillator 12 can move forward and backward in the radial direction of the laser oscillator 12 as described above, and according to the forward and backward movement of the stack block 11 in the radial direction. The approximate cylindrical beam 16 changes its diameter arbitrarily. ,
[0017]
  In order to build up the valve seat, as shown in FIG. 1, the powder 4 of the build-up material is supplied to the entire circumference of the annular groove 1a of the valve seat portion 1 in advance, and the laser oscillator 12 is configured first. Each stack block 11 is moved in the radially outward direction to expand the approximate cylindrical beam 16, and the high output as the approximate circular beam 17 that is approximately circular on the outer peripheral edge of the annular groove 1 a along the processing longitudinal direction. Irradiate. Next, as indicated by an arrow F in FIG. 1, the stack blocks 11 are moved toward each other in a radial direction at a predetermined speed. Then, the approximate circular beam 17 irradiated to the valve seat portion 1 gradually reduces its diameter, and in accordance with this, the powder 4 on the annular groove 1a is sequentially welded to the valve seat portion 1 while melting in an annular shape, CladbeadB (see FIG. 14) is formed.
[0018]
In this case, the approximate circular beam 17 is scanned in the width direction of the annular groove 1a serving as a processing portion, that is, the processing short direction, and therefore, the laser beam is scanned in the processing long direction as in the conventional case (FIG. 14). Compared with the reference), the time required for the scanning is remarkably shortened, and the overlaying of the valve seat is completed in a short time. Further, since it is not necessary to rotate a cylinder as a workpiece as in the prior art, the entire equipment is simplified, and the investment cost of the equipment is reduced accordingly. Moreover, since the processing proceeds in the short direction of processing, the processing start end and the processing end do not overlap with each other even though the processing portion (annular groove) 1a has a closed loop shape, and defects such as cracks and chipping occur. As a result, the processing quality is improved.
Of course, the approximate circular beam 17 may be scanned from the reduced diameter state to the enlarged diameter direction instead of being scanned from the enlarged diameter state to the reduced diameter direction (arrow F direction) as described above. .
[0019]
  FIG. 5 shows a second embodiment of the present invention. In the second embodiment, the valve seat is to be built up with a laser beam in the same manner as in the first embodiment.arrayA pseudo circular beam is formed only by the optical system without using the stack block 11 having the built-in 10. That is, in the second embodiment, the laser beam 20 emitted from the laser oscillator is collected by the parabolic mirror 21 and further passed through the rotating mirror 22 and the oscillating mirror 23 to the valve seat portion 1. To be irradiated. The rotating mirror 22 has a function of rotating a spot (hereinafter referred to as a laser spot) P of the laser beam 20 at a high speed in the processing longitudinal direction along the annular groove 1a of the valve seat portion 1. A pseudo circular beam (pseudo circular beam) 24 is formed on the valve seat portion 1 by high-speed rotation. On the other hand, the oscillating mirror 23 has a function of oscillating the laser spot P in the width direction of the annular groove 1a, that is, the processing short direction, and the oscillating mirror 23 is formed while forming the pseudo circular beam 24 by the rotating mirror 22. In operation, the pseudo-circular beam 24 expands or contracts its diameter.
[0020]
  In order to build up the valve seat according to the second embodiment, as in the first embodiment, the powder 4 of the build-up material is applied to the entire circumference of the annular groove 1a of the valve seat portion 1 in advance. First, the oscillating mirror 23 is appropriately positioned, the laser spot P is rotated at a high speed by the rotating mirror 22, and a pseudo circular beam 24 is formed at a high output on the outer peripheral edge of the annular groove 1a along the processing longitudinal direction. Subsequently, the oscillating mirror 23 is operated. Then, the pseudo circular beam 24 is gradually reduced in its diameter in the same manner as the approximate circular beam 17 in the first embodiment, and the powder 4 on the annular groove 1a is melted in an annular shape in accordance with this, and the valve seat portion. 1 welded sequentially and cladbeadB (see FIG. 13) is formed. The effect of the second embodiment is the same as that of the first embodiment described above, but the size and scanning distance of the circular beam (pseudo-circular beam) 24 can be easily changed only by operating the optical system. Can improve versatility.
  Needless to say, the pseudo-circular beam 24 may be scanned from the reduced diameter state to the enlarged diameter direction instead of being scanned from the enlarged diameter state to the reduced diameter direction as described above.
[0021]
6 and 7 show a third embodiment of the present invention. In the third embodiment, the two plate members 5 and 6 shown in FIG. 15 are to be butt welded with a laser beam. Here, the same as that used in the first embodiment is used. A laser oscillator 26 having a rectangular parallelepiped stack block 25 incorporating the laser diode array 10 is prepared. The laser oscillator 26 is arranged above the plate members 5 and 6 so that the longitudinal direction thereof is along the butted portions 7 of the two plate members 5 and 6 and in a direction orthogonal to the butted portions 7 (direction of arrow A). It can be translated. Here, as shown in FIG. 7, the laser diode array 10 is arranged in a line with its longitudinal direction coinciding with the longitudinal direction of the stack block 25. Further, the laser diode array 10 sets the focal position of the microlens 14 (FIGS. 3 and 4) so that the laser beam 27 is condensed and can be irradiated linearly onto the plate members 5 and 6.
[0022]
In order to perform butt welding according to the third embodiment, first, the laser oscillator 26 is positioned so that the linear beam 28 is formed on the planned line S on one side of the weld bead B to be formed, and the laser A laser beam 27 is emitted from the oscillator 26 at a high output. Simultaneously with the emission of the laser beam 27, the laser oscillator 26 is moved in the direction of arrow A at a predetermined speed, and the linear beam 28 is scanned in a direction orthogonal to the butting portion 7. Then, the butted portions 7 of the two plate members 5 and 6 are melted, thereby forming a weld bead B having a predetermined width and a predetermined depth, and the butt welding is completed.
In this case, the linear beam 28 is scanned in a direction orthogonal to the abutting portion 7 as a processing site, that is, a processing short direction, and therefore, the laser beam is scanned in a direction along the abutting portion 7 as in the prior art, that is, in a processing long direction. Compared with the case where the beam is scanned (see FIG. 15), the time required for the scanning is remarkably shortened, and the welding is completed in a short time.
In addition, such a processing mode can be utilized also when overlaying a line.
[0023]
FIG. 8 shows a fourth embodiment of the present invention. The fourth embodiment is intended to quench the surface of the disk-shaped workpiece 30, and here, the same laser diode array 10 as that used in the first embodiment is incorporated. A laser oscillator 32 having a cylindrical stack block 31 is prepared, and an approximate cylindrical beam 16 (the same as that shown in FIG. 1) emitted from the laser oscillator 32 is condensed to collect the workpiece 30. A condenser lens (convex lens) 33 for irradiating the surface is prepared. A circular beam 34 is formed on the surface of the workpiece 30 by condensing by the condensing lens 33, and the circular beam 34 has an arbitrary diameter depending on the relative position between the condensing lens 33 and the laser oscillator 32. To change.
[0024]
In order to perform surface hardening according to the fourth embodiment, first, the relative positions of the condenser lens 33 and the laser oscillator 32 are set so that the circular beam 34 is aligned with the outer periphery of the disk-shaped workpiece 30. The approximate cylindrical beam 16 is emitted from the laser oscillator 32 at a high output. Simultaneously with the emission of the approximate cylindrical beam 16, for example, the condenser lens 33 is moved at a predetermined speed in a direction approaching the laser oscillator 26 (arrow Z direction). Then, the diameter of the circular beam 34 irradiated on the surface of the workpiece 30 is gradually reduced, and finally the laser beam is irradiated in a spot manner on the center of the workpiece 30. The quenching of the entire surface 30 is finished.
[0025]
In this case, the circular beam 34 is scanned in the radial direction of the workpiece 30, that is, in the processing short direction, and therefore, when the laser beam is scanned in a spiral shape (see Japanese Patent Laid-Open No. 57-140817). In comparison, the time required for the scanning is significantly shortened, and the surface hardening of the workpiece 30 is completed in a short time. Further, since it is not necessary to move the workpiece 30 at all, the entire equipment is simplified, and the investment cost of the equipment is reduced accordingly. Moreover, since quenching proceeds sequentially in the radial direction, processing does not overlap in the radial direction, and tempering due to overlapping processing does not occur. Furthermore, since the circular beam 34 is in a state in which the laser beam is densely continuous in the circumferential direction by the condenser lens 33, the heating temperature in the circumferential direction becomes uniform, and no quenching unevenness occurs.
[0026]
In the fourth embodiment, by forming the stack block 31 into an elliptical shape, a quadrangular shape or the like, it is possible to quench the surface of workpieces having various shapes.
Further, such a processing mode can be used as it is for the overlay processing as in the first and second embodiments. In this case, as shown in FIG. Since there is no need to move 11 or rotate the laser spot P at high speed by the optical system as shown in FIG. 5, the processing cost is significantly reduced.
[0027]
9 and 10 show a fifth embodiment of the present invention. In the fifth embodiment, the teeth of the gear 35 are to be hardened on the surface. Here, the same laser diode array 10 used in the first embodiment is arranged on the inner peripheral side. A laser oscillator 37 having a ring-shaped stack block 36 is prepared. Here, the laser diode array 10 is arranged so that the tooth tip surface 35a, the tooth bottom surface 35b, and the tooth surface 35c of the gear 35 can be individually irradiated, and corresponds to the tooth tip surface 35a, the tooth bottom surface 35b, and the tooth surface 35c. Things are grouped together and the output is adjusted for each group.
[0028]
In order to quench the teeth of the gear 35 according to the fifth embodiment, the gear 35 and the laser oscillator 37 are positioned concentrically, and then the laser beam 38 is emitted from the laser oscillator 37 at a high output. The laser oscillator 37 is moved in the arrow X direction at a predetermined speed. Then, a deformed beam 39 (FIG. 9) that follows the tooth shape is formed on the outer periphery of the gear 35, and the deformed beam 39 is scanned in the axial direction of the gear 35. At this time, since the output of the laser beam 38 is adjusted corresponding to the tooth tip surface 35a, the tooth bottom surface 35b, and the tooth surface 35c, the gear 35 is uniformly heated in the circumferential direction. The part is surface hardened uniformly.
[0029]
【Example】
Example 1
A Cu—Ni—Fe—Si—B based alloy powder as a build-up material is deposited on an aluminum alloy substrate in an annular shape so as to have an inner diameter of 23 mm and an outer diameter of 33 mm, and the first embodiment (FIG. Overlay processing was performed under the following conditions according to the processing mode of 1).
Laser used: Semiconductor laser (wavelength 0.94 μm)
Laser output: 10KW
Line width of approximate circular beam 17: 1 mm
Scanning speed of approximate circular beam 17: 0.1 m / min
In this case, the scanning time (processing time) of the approximate circular beam 17 is as extremely short as 0.05 minutes since the scanning distance (processing length) is 5 mm (= [33-23] / 2). However, as shown in FIG. 11, a clad bead 41 having a width W of about 5 mm and a height H of about 2 mm on the aluminum alloy substrate 40 has a smooth surface and no internal defects such as bubbles and voids. Been formed. In addition, it was confirmed that there was almost no penetration of the substrate 40 and that the change in the components of the clad beads 41 due to the component dilution of the base material (substrate material) was almost negligible.
[0030]
Example 2
In the same manner as in Example 1, Cu—Ni—Fe—Si—B alloy powder is placed on an aluminum alloy substrate in an annular shape so as to have an inner diameter of 23 mm and an outer diameter of 33 mm, and the processing of the second embodiment is performed. Overlay processing was performed under the following conditions according to the mode (FIG. 5).
Laser used: CO₂Laser (wavelength 10.6μm)
Laser output: 10KW
Rotational speed of laser spot point P: 1 kHz (circumferential speed 100 m / sec)
Line width of pseudo circular beam 24: 1 mm
Scanning speed of approximate circular beam 17: 0.1 m / min
Also in this case, the scanning time (processing time) of the pseudo circular beam 24 is as extremely short as 0.05 minutes, but the clad bead 41 having the same shape and quality as the first embodiment is formed. It was.
[0031]
Example 3
  Two plates made of JIS SPFC440 are butted together and processed under the following conditions according to the processing mode of the third embodiment (FIG. 6).Butt weldingWent.
    Laser used: Semiconductor laser (wavelength 0.94 μm)
    Laser power: 6KW
    Line width of the linear beam 28: 1 mm
    Scanning speed of the linear beam 28: 0.1 m / min
    Scanning distance of the linear beam 28: 5 mm
  As a result, as shown in FIG. 12, a weld bead 44 having a width W of about 5 mm and a depth D of about 3 mm at the abutting portion of the two plate members 42 and 43 has a smooth surface and the inside of bubbles, holes, etc. It was formed without defects.
[0032]
Example 4
  For gears with a gear diameter of 25 mm and a tooth width of 10 mm, a laser oscillator 37 with an inner diameter of 30 mm is used under the following conditions according to the processing mode of the fifth embodiment (FIG. 9).QuenchingWent.
    Laser used: Semiconductor laser (wavelength 0.94 μm)
    Laser output: 2.5KW
    Line width of deformed beam 39: 1 mm
    Scanning speed of deformed beam 39: 0.1 m / min
  As a result, as shown in FIG. 13, a hardened layer 46 having a depth D of about 2 mm was uniformly formed on the teeth of the gear 45.
[0033]
Comparative example
As in Example 1, Cu—Ni—Fe—Si—B based alloy powder was placed on an aluminum alloy substrate in an annular shape so as to have an inner diameter of 23 mm and an outer diameter of 33 mm, and the conventional processing shown in FIG. Overlay processing was performed under the following conditions depending on the style.
Laser used: CO₂Laser (wavelength 10.6μm)
Laser power: 4KW
Condensing diameter of laser beam L: 2 mm
Oscillation width of laser beam L: 5 mm
The oscillation frequency of the laser beam L: 200 Hz
Laser beam scanning speed in the circumferential direction: 1 m / min
As a result, the same clad bead 41 as in Example 1 was formed, but the penetration of the substrate 40 was observed at the overlap between the processing start end and the processing end, and there was a risk of component dilution by the base material. Further, in this comparative example, since the processing length is about 100 mm, the processing time is about 0.1 minutes, which is twice that of Example 1 of the present invention.
[0034]
【The invention's effect】
  As described above, according to the invention according to claim 1, since the laser beam shaped in the processing longitudinal direction is scanned in the processing lateral direction, the processing time can be greatly shortened and the productivity is improved. It will greatly contribute to. Moreover,A laser beam shaped into a closed loop shape is scanned in either the reduced diameter direction or the expanded diameter direction in the short direction of processing.As a result, there is no overlap of processing, ensuring the desired processing quality stably.In particular, tempering due to reheating can be eliminated, and stable application to quenching is possible, and its utility value is significantly increased.
[0035]
  Claim 2According to the invention, in addition to the effect of the invention according to the first aspect, the laser beam irradiation shape can be set to an arbitrary size only by operating the optical system, so that versatility is improved.
[0036]
  Also,Claim 3According to the invention, since the output of the laser boom can be adjusted according to the irradiation site, it is possible to process the processing site having unevenness, and the application range is expanded.
[0037]
  Also,Claim 4According to the invention related toClaims 1 to 3In the invention according to any one of the above, one of processes selected from overlaying, welding, and quenching can be performed in an optimum state.
  further,Claim 5According to the invention related toClaims 1 to 4Since the laser processed product is processed by the laser processing method according to any one of the above, and there is no overlapping portion of the processed layers, it can be stably used even in a field where quality requirements are severe.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a first embodiment of a laser processing method according to the present invention.
FIG. 2 is a plan view showing a structure of a stack block including a laser diode array used in the first embodiment.
FIG. 3 is a perspective view showing a structure of a laser diode array.
FIG. 4 is a side view showing the structure of a laser diode array.
FIG. 5 is a perspective view schematically showing a second embodiment of the laser processing method according to the present invention.
FIG. 6 is a perspective view schematically showing a third embodiment of the laser processing method according to the present invention.
FIG. 7 is a plan view showing a structure of a stack block including a laser diode array used in the third embodiment.
FIG. 8 is a perspective view schematically showing a fourth embodiment of the laser processing method according to the present invention.
FIG. 9 is a perspective view schematically showing a fifth embodiment of the laser processing method according to the present invention.
FIG. 10 is a schematic diagram showing a laser irradiation state in the fifth embodiment.
FIG. 11 is a schematic diagram showing a state of a stacked beam obtained in one embodiment of the present invention.
FIG. 12 is a schematic view showing a state of a welding beam obtained in another example of the present invention.
FIG. 13 is a schematic view showing a hardened state of a gear obtained in still another embodiment of the present invention.
FIG. 14 is a perspective view schematically showing an embodiment of conventional laser overlay processing.
FIG. 15 is a perspective view schematically showing an embodiment of a conventional laser butt welding process.
[Explanation of symbols]
1 Valve seat
4 Powder of overlaying material
5, 6 Plate material
10 Laser diode array
11, 25, 31, 36 Stack block
12, 26, 32, 37 Laser oscillator
16 Approximate cylindrical beam
17 Approximate circular beam
21 Parabolic mirror
22 Rotating mirror
23 Oscillating mirror
24 pseudo circular beam
28 Linear beam
30 Workpiece
33 condenser lens
34 Circular beam
35 gears
39 Profile beam

Claims (5)

By irradiating the workpiece with the laser beam so that it is focused at the processing site, the laser beam irradiation shape is linear in the processing longitudinal direction on the workpiece, and the closed loop shape is matched to the closed loop processing site And processing the processed part by scanning the laser beam shaped into a linear and closed-loop shape in either the reduced diameter direction or the expanded diameter direction while maintaining the linear shape. A laser processing method characterized by the above.   The laser processing method according to claim 1, wherein the laser beam is rotated at a high speed by operating the optical system to shape the laser beam irradiation shape into a pseudo closed loop shape.   2. The laser processing method according to claim 1, wherein a laser beam irradiation shape is shaped using a laser diode array arranged in a predetermined shape.   The laser processing method according to any one of claims 1 to 3, wherein the processing on the processing site is one selected from overlaying, welding, and quenching.   5. A laser processed product processed by the laser processing method according to claim 1, wherein there is no overlapping portion of processed layers.

Images